Avoid "mac clock not ready" panic in iwm(4).

The point of iwm_nic_assert_locked() is to verify that iwm_nic_lock() has
been called somewhere up in the call stack. Checking our own lock counter
is sufficient for this purpose.

If locking the device worked then these registers had the expected state at
that time and our lock counter was incremented. Apparently if the device runs
into some issue later the state of these registers may change and trigger
these panics. Instead we want to handle such failures gracefully and reset
the device.

problem reported by steven@
ok kettenis@

diff --git a/sys/dev/pci/if_iwm.c b/sys/dev/pci/if_iwm.c
index 4b50246..2d1b4f4 100644 (file)
--- a/sys/dev/pci/if_iwm.c
+++ b/sys/dev/pci/if_iwm.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_iwm.c,v 1.325 2021/05/16 15:10:20 deraadt Exp $    */
+/*     $OpenBSD: if_iwm.c,v 1.326 2021/05/31 08:40:41 stsp Exp $       */
 
 /*
  * Copyright (c) 2014, 2016 genua gmbh <info@genua.de>
@@ -1069,11 +1069,6 @@ iwm_nic_lock(struct iwm_softc *sc)
 void
 iwm_nic_assert_locked(struct iwm_softc *sc)
 {
-       uint32_t reg = IWM_READ(sc, IWM_CSR_GP_CNTRL);
-       if ((reg & IWM_CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY) == 0)
-               panic("%s: mac clock not ready", DEVNAME(sc));
-       if (reg & IWM_CSR_GP_CNTRL_REG_FLAG_GOING_TO_SLEEP)
-               panic("%s: mac gone to sleep", DEVNAME(sc));
        if (sc->sc_nic_locks <= 0)
                panic("%s: nic locks counter %d", DEVNAME(sc), sc->sc_nic_locks);
 }